These days, auto show models such as Strauss are also narrators, providing information — basic and arcane — about the vehicles.

"You can come up to me and ask, 'What's the 0-to-60 horsepower torque top-speed compression ratio (of a car)' and I could give you an informed answer," said Strauss, who has been with Cadillac for three years.

Behold the evolution of the auto show model, part of the Chicago event since the 1930s, when the event was held at the since-demolished International Amphitheatre on the South Side.

Chicago Auto Show historian M.J. Frumkin says the models' role began to change in the 1980s. That's when talent agencies who furnish the models encouraged them to learn more about the vehicles.

"Usually, the people who come to the show aren't all that knowledgeable about cars, and people wouldn't want to listen to an engineer providing technical details," Frumkin said. Not to mention, in 2011, 74 percent of Chicago Auto Show attendees were men. "So why not have a beautiful woman provide that information about the car, to get them interested?"

Models say they can earn anywhere from $200 to $500 per day. Caitlyn McCabe started working as a promotional model while studying communications at DePaul and says she now brings in about $45,000 a year from auto shows.

"It's a pretty good way to make a living, especially if you are an actor, a model or in communications," said McCabe, 26. "It's my only source of income."